The Effects of Cover Crops on Runoff, Erosion, and Off-Site N and P Transport

Author(s): Spencer, D.; Krutz, J.; Locke, M.; Henry, B.; Golden, B.

There has been increasing interest in incorporating cover crops into production systems in the Midsouthern United States. Studies were established in Stoneville, MS to determine the effects of four cover crops on water use efficiency, runoff, erosion, and off-site N and P transport in a continuous corn production system. Treatments consisted of a reduced till/no cover (RTNC) as a control, reduced tillage with cereal rye (CR) (Secale cereal L.), reduced tillage with Austrian winter pea (AP) (Pisum sativum L.), reduced tillage with tillage radish (TR) (Raphanus sativus L.), reduced tillage with crimson clover (CC) (Trifolium incarnatum L.), and no till/no cover (NTNC). A portable rainfall simulator was used to simulate precipitation and the resulting runoff was captured from each plot to determine flow, sediment load, and N and P transport. Austrian pea increased infiltration by 24.7% relative to the RTNC plots. CR resulted in higher amounts of PO4 and total Kjeldahl nitrogen (TKN) in the runoff water than the control and higher amounts of NH4 than all other treatments except the RTNC. Also, furrows which received equipment tire traffic had lower amounts of NH4 and TKN than furrows not receiving tire traffic. Lastly, corn grain yield was 40 and 45% lower in the AP and CR plots, respectively, than the RTNC control. These results indicate that there is potential for some cover crops to improve infiltration in the Mid-south, however, more research is required to understand the effects on corn grain yield and nutrient transport.

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